1. Technical Field
The present invention relates to an ink composition, an ink set containing the ink composition, a recording method involving use of the ink composition, and a recorded matter produced with the ink composition.
2. Related Art
A variety of methods for recording images on recording media have been traditionally known. In an ink jet recording method, for example, fine ink droplets are ejected from a nozzle opening of an ink jet recording head to record images and characters on recording media.
In order to keep high image quality for a long period, images recorded on recording media need to have characteristics such as satisfactory color development, light resistance, and water resistance. In a technique disclosed in JP-A-2005-15813, for instance, cyan, magenta, and yellow ink compositions containing specific pigments which can impart satisfactory color development, light resistance, and water resistance are used for recording, which enables high image quality to be kept for a long period.
In the ink and ink set disclosed in JP-A-2005-15813, the characteristics of the ink composition, such as color development, light resistance, and water resistance, however, depend on the structure of the colorant itself, such as a structure contributing to color development or a structure exhibiting unsatisfactory ultraviolet resistance or water resistance; thus, a colorant which serves for high color development but exhibits unsatisfactory light and water resistance cannot be used. Use of such a colorant problematically causes difficulty in keeping high image quality for a long period without discoloration.
Yellow colorants exhibit unsatisfactory light resistance as compared with cyan and magenta colorants, and only limited types of colorants can be used in outdoor environment in which a recorded matter is directly exposed to sunlight and rain. Long-term use of such yellow colorants in outdoor environment involves additional treatment such as lamination, which disadvantageously requires further time and expense and unwanted production processes.